The Wind Stone is an artifact slightly shorter than Sonic the Hedgehog's full height. It has a grey square rock stand with an almost ellipsoid green crystal fixed vertically on a green ring on top of it. Inside the green crystal, the Wind Stone has a symbol resembling a vortex.
In Sonic Adventure, and its enhanced port Sonic Adventure DX: Director's Cut, the Wind Stone appears in Sonic, Tails and E-102 Gamma's storyline, where it can be found in front of the front door to Tails' Workshop in the Mystic Ruins Station Area Adventure Field. In Sonic and Tails' stories, the Wind Stone appears after the player defeats the Egg Hornet, and in E-102 Gamma's story it can be found when Gamma arrives in the Mystic Ruins after the Egg Carrier crashes.
The Wind Stone is to be taken by the player to the cave with wind blowing through, on the left of the open area in front of the train station in the Mystic Ruins Station Area Adventure Field. There, the Wind Stone must be placed on a pedestal with a square green crystal in order to open the entrance to Windy Valley.